1. Field
The subject matter disclosed herein relates to electronic devices, and more particularly to methods and apparatuses for use in a mobile device for determining a location of the mobile device within a multilevel physical structure.
2. Information
The Global Positioning System (GPS) represents one type of Global Navigation Satellite System (GNSS), which along with other types of satellite positioning systems (SPS) provide or otherwise support signal-based position location capabilities (e.g., navigation functions) in mobile devices, and particularly in outdoor environments. However, since some satellite signals may not be reliably received and/or acquired by a mobile device within an indoor environment or other like mixed indoor/outdoor environments, different techniques may be employed to enable position location services.
For example, mobile devices may attempt to obtain a position fix by measuring ranges to three or more terrestrial transmitters (e.g., wireless access points, beacons, cell towers, etc.) which are positioned at known locations. Such ranges may be measured, for example, by obtaining a MAC ID address from signals received from such transmitters and obtaining range measurements to the transmitters by measuring one or more characteristics of signals received from such transmitters such as, for example, signal strength, a round trip delay time, etc.
These and other like position location and navigation techniques tend to be of further benefit to a user if presented with certain mapped features. For example, mapped features may relate to or otherwise identify certain physical objects, characteristics, or points of interest within a building or complex, etc. Thus, in certain instances, an indoor navigation system may provide a digital electronic map to mobile device upon entering a particular indoor area, e.g., in response to a request for navigation assistance data. Such a map may show indoor features such as doors, hallways, entry ways, walls, etc., points of interest such as bathrooms, pay phones, room names, stores, etc. Such a digital electronic map may be stored at a server to be accessible by a mobile device through selection of a URL, for example. By obtaining and displaying such a map, a mobile device may overlay a current location of the mobile device (and user) over the displayed map to provide the user with additional context.
Accordingly, with the plethora of information that may be provided to and/or otherwise used by a mobile device, there is a continuing desire to reduce the amount of data and/or the size of data files that may need to be transmitted, stored, and/or processed by the various devices and communications resources.